1. Technical Field of the Invention
This invention relates generally to wireless communication systems and more particularly to an adaptive piconet wireless communication system.
2. Description of Related Art
FIG. 1 is a schematic block diagram of a Bluetooth compliant piconet that includes a master device and a plurality of slave devices. In accordance with the Bluetooth specification, the master device and each the slave devices includes a radio frequency transceiver that functions in accordance with one or more versions of the Bluetooth standard to support the conveyance of packets via a wireless communication channel. In this illustration, a data or voice packet is transmitted via the wireless communication channel between the master device and plurality of slave devices.
As shown, the Bluetooth packet includes a header section, which may include an access code and a packet header, and a payload section. The payload section may include a data section or a voice section and may be up to 3.125 milliseconds (e.g., 625 μSec*5) in duration.
The data section is divided into a plurality of slots, each 625 microseconds in duration. As is further shown, the 1st slot is allocated to the master and may be used for polling the slaves with respect to whether the slaves have data to transmit to the master. The next four slots may be allocated to each of the slaves for transmitting their respective data as well as providing a packet acknowledgment. In accordance with the Bluetooth standard, frequency hopping is used on a slot-by-slot basis such that for the 1st slot, which is allocated to the master, a 1st frequency (f1) is used. For the 2nd slot, a 2nd frequency (f2) is used and so on. As is known, the frequency hopping sequence is unique for each piconet and is determined by the master device. The master device establishes the frequency hopping scheme and provides it to the slave devices. While the frequency hopping enables communications to avoid frequencies that may have high levels of noise or other problems, it does so at the cost of processing time to change the transceivers frequency response from one frequency to the next in the frequency hopping sequence.
The data section of the payload has a further restriction with respect to slot positioning for the master. In particular, the restrictive slot positioning follows a pattern of master-slave-master-slave, master-slave-slave-master-slave-slave, master-slave-slave-slave-master-slave-slave-slave, et cetera. As such, once the pattern is established for the particular packet, it must be adhered to even if no data is available for transmission during an allocated slot.
The voice section of the payload includes a slot allocation of master-slave-master-slave. Each allocated master slot includes a master voice poll packet to a particular slave. The next slot is allocated for the particular slave to respond with its voice data and a packet acknowledgment. As shown, from slot-to-slot, the frequency changes in accordance with the frequency hopping sequence established by the master device. While the current structure of the data voice packet enables a multitude of devices to communicate in a piconet fashion, it has the frequency hopping on a per-slot-basis requirement and also has the restrictive slot positioning of the master-to-slave. As such, for certain applications where the slaves' data and voice payload requirements vary, such a rigid structure limits the overall efficiency of the piconet. In particular, a gaming system where the master device is a game console and the slave devices are game controllers, the amount of data between the slave devices and master device will vary significantly over time. Thus, efficiency of a gaming system that follows the rigid structure of a Bluetooth packet is limited.
Therefore, a need exists for a method of providing an adaptive piconet protocol to overcome the above mentioned efficient limitations of a piconet.